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Questions tagged [nfc]

Near Field Communications - In antennae theory Far Field radiation is that RF energy that gets transmitted, Near Field is the RF energy that typically does not propagate , unless it is intercepted by a special antenna. It is used to transmit signals over short distances without transmitting widely, it is used in wireless communications for very short ranges on the order of meters and is harder to intercept because you have to be close.

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IC on Digikey is 5x more expensive than board containing same IC on Alibaba: How? [closed]

I built a prototype using an NFC board I bought from Alibaba for 1$ (https://www.alibaba.com/showroom/rfid-rc522.html). It claims to use the NXP MFRC522 IC, and if I look on the board the chip has ...
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how to enlarge the reading range between the 13.56MHz NFC reader and tags with ISO15693?

I use TI devices, DLP7970ABP and RF430FRL152H tag. In order to enlarge the reading range, I buy a power amplifier and a large antenna(430mm*330mm). If I only disconnect the original antenna on the ...
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What is the difference between ISO/IEC standards and NFC Forum Type specifications?

As far as I understand, NFC Forum Type specifications are based on existing ISO/IEC standards so there is no theoretical difference there. NFC Forum Type specifications however go one step further and ...
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My antenna tuning component values worked on a fresh board previously. Now they're not working. What could be causing this?

This is one of those hardware questions that's making me bang my head against a wall. About six weeks ago I spent a day tuning the NFC antenna on my board. I ended up using ~71pF of shunt capacitance ...
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26 views

NFC Antenna Feed Lines

I've designed a number of boards in the past that use NFC but I don't think the RF performance has ever been exceptional. These boards have an NFC chip (generally the STM M24SR64-YMN6T/2) connected to ...
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27 views

S11 parameter measurements of NFC PCB antenna by VNA

I'm trying to measure the S11 parameter of the NFC PCB antenna (actually PCB coil) by VNA. Desired Smith chart pattern is like the below picture (probably with different values, because of different ...
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32 views

Writing data into a SPI Flash using NFC?

I have a 16 Mbit SPI flash. I want to write data to the SPI flash using NFC. I know there are multiple NFC+MCU series out there that can do this. However, the NFC+MCU require JTAG, LDOs, ..etc. The ...
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29 views

Android NFC library - Command not recognized

To access more than 2kb of data from TI Rf430 transponder IC, a custom command (0xC0) in specific format needs to be sent. On sending the custom command, command not recognized (0x01) is the response ...
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1answer
58 views

Reading NFC tag from a slightly longer distance

Presently, my problem is that I have this NFC/RFID Tag, and due to the small antenna on the tag, it needs to make direct contact with the reader (presently tested using both a smartphone w/ NFC ...
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1answer
59 views

How can I make my RFID reader restrict itself to the tag in the closest proximity and read only this tag?

I'm looking for a way to detect the user closest to a certain object that has the RFID reader attached to it. Therefore I need my RFID reader to restrict itself to the user closest to it and not read ...
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How much maximum voltage and current passive NFC generate at FD and VSS pin

I am working on NFC tag - NTAG 21X series and I can see there are 2 pins FD and VSS. I want to know how much maximum current and voltage it can generate when it come closer to active NFC tag ( or ...
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Designing NFC PCB antenna in multi layer instead of usual 1 layer antenna

I'm working on a new NFC reader board with serious limitations in dimension of the board. This cause smaller antenna coil, which affect on range and power of antenna. My boss suggested to design coil ...
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NFC spectrum analysis, weird frequencies showing

I apologize for the picture quality, I did not have an opportunity to export the screenshots. I have a problem properly interpreting this signal. The subcarrier peak is visible but the data seems to ...
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1answer
75 views

NFC/RFID device sending URL to NFC-enabled smartphone at 20-30cm

I am very new to this so please bear with me. I have read many questions but I haven't quite found a suitable one for what I would like to do. I would need a NFC/HF RFID device able to send an URL to ...
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178 views

difference between ISO 14443 vs ISO 18092 and collision detection

I have been studying about contactless payment specifications and protocols and I have few questions about them. Are ISO-14443 and ISO-18092 called NFC and RFID in general terms, or are they a ...
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What is this weird EMV pin on my credit card?

I recently got a Venmo card, which is my first card with contactless support. I was looking at the EMV pins and noticed a very weird design. In the middle of the ground pin there is this long, thin ...
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205 views

Can you find what RFID frequency is used in a tag and then edit it? [closed]

A short background: my brother has membership at a gym that uses small RFID tags ("near field", I suppose, as you need to tap them against the spinning gate in order to open it) and after changing his ...
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1answer
37 views

is it true that whether a POS can read an NFC card, that POS is compatible with HCE?

I was wondering if the host card emulation would produce the same result as an physical contactless card is producing.
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1answer
204 views

Repairing an RFID antenna? [closed]

I have an RFID antenna that seems to be on a custom PCB. The issue I have is that the antenna on one side works fine, but the other side does not. I'm not sure if it is even possible or worthwhile to ...
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2answers
103 views

Near-field-communication / NFC at no cost

My company is developing and producing measurement devices. To quality check and adjust the full devices automatically, we need to be able to read the display indication and trigger functions like ...
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44 views

NFC Antenna matching

I am trying to follow the TI document on NFC antenna matching for the TFR7970A chipset. http://www.ti.com/lit/an/sloa241b/sloa241b.pdf I am under linux, and while I could try wine to use the smith ...
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Sensing a tag passes through a virtual “fence”

We have two cats who like to hide in our house. It would be great to know where they are in the house. At first I thought about setting up an indoor localization system (iBeacon, etc.) in place, but ...
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1answer
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On board 13.56MHz RFID antenna design

I recently stumbled upon a two-in-one NFC key designed by N-O-D-E and was astonished. Although its original purpose is for security, I love the idea of using tact ...
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Designing NFC/RFID PCB

I am building a prototype for a wireless medical sensor, and I use an Xbee for the communication between the sensor and the controller. My problem is pairing. The sensor is about the size of a ...
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1answer
708 views

What is the typical power that is transmitted through NFC from a smartphone

I think the question is clear. I only need a reference value, like is it in the range of 1mW or 10mW or 100mW. Clearly this will vary among smartphones. Also do you think it is possible to set the ...
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1answer
27 views

Need help with nfc on phone [closed]

I’m looking for a quick and easy way to extend the range on my Samsung s4 I’m currently using a iPhone 5 but I use a my old Samsung s4 for my music and I have these nfc connect speakers and was ...
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2answers
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How is a NFC “connected tag” different from a full blown NFC reader?

I have played with NFC in the past, but those were full blown "NFC readers" based on NXP pn53x chips. I want to know, how is a so called "Connected tag" different from NFC readers? I found this chip ...
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2answers
838 views

What factors affect the read distance of NFC chips, and how?

I'm trying to understand how to improve the reading distance of an NFC system. So far, my understanding is that there are a few main factors in the read distance: Size/shape of the antenna on the NFC ...
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1answer
533 views

“Antenna matching networks for dummies”?

I'm working on a project where I'm building a custom NFC antenna that will be connected to a PN532 NFC controller. The antenna has already been designed (for 13.56 MHz) and built, the PN532 is also ...
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65 views

What prevents (illegitimate) operation of NFC with higher power?

I was going to post this on Information Security, but Elecrical Engineering may possibly be a better fit since it's more about the technical side. Like most people nowadays, I am left with no choice ...
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1answer
61 views

PN53x with emulate nfc

I saw that many of nfc reader/emulate based on PN53x chipset of NXP. But the disadvantage of this chipset is , you can't emulate ISO14443-B why is PN53x chipset ...
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How to read NFC tags Simultaneously?

I look for a solution for a problem in my project. The idea of the project is to create a smart library which help us to know where every book located in every period of time. Picture : The idea ...
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459 views

Is possible to update the firmware of the PN532 chip?

I want to know if is possible to update the firmware of the NFC chip PN532 from NXP. If it is, how can this be done? If this isn't the appropriate Stack exchange site please move the question.
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2k views

RFID solution for reading multiple tags

I am working on a Robot-project where a sub task is have to check how many and which RFID-tags are placed in a bucket. Multiple tags will be placed into the bucket - so I run into the problem with ...
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116 views

Blocking NFC-Tags without metal

I got this NFC-Tag and I try to do something, so that this tag can't be recognized by any nfc-tag-reader anymore. But I want to easily change this state, so that I can easily 'free' the nfc-tag so ...
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Is the ability of reading NFC-tags in smartphones specified?

Is the NFC-reading-module in smart phones in a way specified (e.g. in ISO 18092) as that every smart phone has the same 'power' of reading NFC-tags. I am not an electrical engineer. What I am trying ...
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1answer
272 views

Does this rfid reader work with the nfc ring? [closed]

I bought a rfid rc522 and hooked it up with an arduino nano. The rc522 reader says it reads at a frequency of 13.56Mhz. The nfc ring is also at 13.56MHz but i can not get it working with it. The ...
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2answers
392 views

Function of solid plane in the NFC antenna

Below picture shows 2 NFC antenna designed by NXP for their NFC chips . As you can see there are square planes in the middle of antenna,these planes have no Nets(does not connected to any where ). ...
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3answers
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I need a cheap solution for wireless connection in a parking [closed]

I want to build a parking system "besides some busy streets" that when a car parks in the specified locations, the system charges something like a card that it's exist on the car or something like an ...
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1answer
825 views

I2C Slave ACK not driving down sufficiently

My I2C slave is not pulling down the bus all the way for the ACK. I have tried replacing 1.5k pullup with 10k pullup, but the ACK voltage remains the same (1.6V). System Voltage: 2.5V Master: ...
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2answers
488 views

Increasing NFC range by adding a battery power source

I am pretty new to NFC but I was thinking if it possible to increase the range of an passive NFC tag by attaching a power source. As per my understanding a passive tag has low range because the EM ...
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1answer
53 views

RFID identify and send to mobile app

I am planning to make a device and a mobile app with RFID. Main objective is, There will be set of square blocks(5), each block can contain RFID, each denotes a number. I will have a placeholder ...
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1answer
4k views

What is the maximum power transmitted through NFC that can be harvested?

What is the maximum power an NFC-enabled card can draw from a contactless payment terminal? What are the determinants (i.e. card reader voltage)? What techniques are available for harvesting this ...
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1answer
152 views

What is the frequency of response of a FDX-B RFID Tag protocol?

I am using the HTRC110 IC for driving the antenna, and the responses are always controlled by the SCLK signal. But when I send the command to read the RFID response, the IC enters in a transparent ...
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1answer
277 views

nfc antenna coil wth external capcitor

I have a NFC chip [Mifare Desfire EV1] which has input capacitance of 17 pF(pico farad). I got ready-made antenna (Datasheet of Antenna) which has induction of 1.8 uH(Micro Henries). So by simple ...
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1answer
88 views

Best way to get exact proximity between devices [closed]

Need to get exact distance between devices like beacons or RF devices, exact means; about ~10cm tolerance. Here is what I need; I will use some devices like RF module or beacons on road and I need to ...
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1answer
144 views

Boosting NFC range for mobile device

I am a type one diabetic and they just released a new advancement in technology. Its a sensor that transmits via NFC to your smart phone. But the range is one inch to be able to read the blood sugar. ...
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1answer
142 views

Near field intensity in terms of antenna thickness

I've been told that the near field created by a thin wire "antenna" goes to infinity in a neighborhood of the antenna as the wire gets thinner and thinner. However, I'm not able to find any tables or ...
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1answer
215 views

Elegant non-mechanical way to switch on battery-powered device the first time

For a primary-battery powered device, that will be stored for a period of time before first use, what is the most elegant non-mechanical* way to switch it on for the first time, after which it will ...
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2answers
558 views

Using RFID antenna to read NFC tag

I have a simple question, I want for a school project read NFC tags from a large range, can I use a RFID antenna to read the NFC tag ? I want to know if the RFID antenna is going to work and read the ...